Substrate treatment method and substrate treatment apparatus

ABSTRACT

The present invention is a substrate treatment method in which a treatment by supplying a treatment solution from a nozzle to a substrate is successively performed for a plurality of substrates, which comprises the step of, during the performance of the successive treatments, performing between the treatments a plurality of pre-dispenses for different purposes of the treatment solution, wherein at least a recipe of the treatment solution to be pre-dispensed or a start condition of the pre-dispense is determined for each of the pre-dispenses. According to the present invention, the pre-dispense can be performed at a necessary and sufficient frequency to shorten the suspension time due to the pre-dispenses in the substrate treatment. This improves the throughput and reduces the number of pre-dispenses, resulting in reduced consumption of the treatment solution.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of Divisional patentapplication Ser. No.: 11/188,890, filed on Jul. 26, 2005, now abandonedwhich, in turn is a Divisional Application of Parent patent applicationSer. No. 10/347,438, filed on Jan. 21, 2003, now U.S. Pat. No. 7,094,440which is based on Priority Documents JP-2002-012810 filed on Jan. 22,2002 and JP-2002-012805 filed on Jan. 22, 2002, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate treatment method and asubstrate treatment apparatus.

2. Description of the Related Art

In fabrication processes of semiconductor devices, a resist coatingtreatment is performed in which a resist solution is supplied to, forexample, a semiconductor wafer (hereafter referred to as a “wafer”) toform a resist film on the front face of the wafer.

This resist coating treatment is normally performed in a resist coatingunit. The resist coating unit is provided with a nozzle for supplying apredetermined amount of the resist solution to the wafer. The nozzle isconnected to a storage tank, which is a supply source of the resistsolution, via a pipe. This pipe is provided with, for example, a pumpfor feeding the resist solution by pressure, a filter for removingimpurities, an open/close valve for controlling discharge of the resistsolution, and so on. These members constitute a supply mechanism of theresist solution. The resist solution in the storage tank is dischargedfrom the nozzle via the pump, filter, open/close valve, and so on. Inthe resist coating unit, treatment is repeatedly performed in which theresist solution is supplied to wafers carried into the unit insuccession.

By the way, in the resist coating unit, a pre-dispense of once drainingthe resist solution staying in the pipe via the nozzle hasconventionally been performed before actual supply to a substrate. Thepre-dispense in the prior art has been performed for the supplymechanism in the same system based on a single recipe and startcondition. The reason why the pre-dispense has been performed based onthe single recipe and start condition is to simplify control of theresist coating unit which normally has a supply mechanism in a pluralityof systems.

However, there are a plurality of purposes of performance of thepre-dispense in the resist coating unit. The pre-dispense includes, forexample, one performed at the time of change of lot for stabilizing thedischarge amount of the resist solution from the nozzle, one forremoving bubbles staying in the filter and pump, one for preventingdrying of the nozzle and the like, and so on. The recipes including thedischarge amounts of the respective pre-dispenses required for attainingthese purposes and start conditions of the pre-dispenses are actuallydifferent from each other depending on their different purposes.

If it is desired to accomplish all the purposes of pre-dispenses by onekind of setting in the same supply mechanism as in the prior art, it isnecessary to match, for example, regarding the frequency ofpre-dispenses, the start condition to the setting of a pre-dispensewhich has a relaxed start condition, that is, which needs to beperformed most frequently. The discharge amount also needs to be matchedto the amount of a pre-dispense having the largest discharge amountamong many pre-dispenses.

Besides, the resist solution coating treatment successively performedfor wafers is performed in succession for every lot of substrates. Whenthe supply of the resist solution to the wafer is stopped, the resistsolution remains in the nozzle and the supply pipe. When left standingfor a long time, the remaining resist solution dries or changes inquality. Therefore, a pre-dispense is performed at a break betweentreatments for lots of wafers as described above. Conventionally, thepre-dispense performed at a break between the lots has been performeduniformly every change of lot without fail.

During the pre-dispense, however, the treatment for wafers is suspended,and thus if its recipe is matched to that of the pre-dispense whichneeds to be performed most frequently, the throughput of the treatmentis significantly decreased. Further, the resist solution discharged whenthe pre-dispense is normally disposed, resulting in increased amount ofthe resist solution going to waste. This problem also applies to thecase in which the pre-dispense is performed every change of lot.

SUMMARY OF THE INVENTION

The present invention is made in the above viewpoints, and it is anobject of the present invention to improve the throughput and to reducethe consumption of a treatment solution when performing pre-dispensesfor respective purposes, by omitting unnecessary pre-dispenses.

According to a first aspect of the present invention, the presentinvention is a substrate treatment method in which a treatment bysupplying a treatment solution from a nozzle to a substrate issuccessively performed for a plurality of substrates, comprising thestep of, during the performance of the successive treatments, performingbetween the treatments a plurality of pre-dispenses for differentpurposes of the treatment solution, wherein at least a recipe of thetreatment solution to be pre-dispensed or a start condition of thepre-dispense is determined for each of the pre-dispenses.

According to the present invention, the start condition and the like aredetermined for each of the plurality of pre-dispenses, so that thepre-dispense can be performed in accordance with a purpose. For example,the pre-dispense can be performed at a necessary and sufficientfrequency for attaining each purpose to shorten the suspension time dueto the pre-dispenses in the substrate treatment, resulting in improvedthroughput. Further, it is possible to omit unnecessary pre-dispenses tothereby reduce the consumption of the treatment solution by thepre-dispenses.

According to a second aspect of the present invention, the presentinvention is a substrate treatment method in which a treatment bysupplying a treatment solution to a substrate is successively performedfor a plurality of substrates, comprising the step of performing apre-dispense of the treatment solution at a break between lots of thesubstrates, wherein the step of performing the pre-dispense is performedonly when the kind of the supplied treatment solution is changed betweenthe lots.

According to the present invention, the pre-dispense is performed onlywhen the kind of the treatment solution is changed between the lots andnot every change of lot as in the prior art, resulting in reduced numberof pre-dispenses. Therefore, the total consumption of the treatmentsolution is reduced for reduced cost. Further, when no pre-dispense isperformed, the treatment is not suspended, so that the treatment for thesubsequent substrate can be started immediately, resulting in improvedefficiency of treating substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a coating and developing treatmentsystem to which an embodiment of the present invention is applied;

FIG. 2 is a plane view schematically showing the configuration of thecoating and developing treatment system in FIG. 1;

FIG. 3 is a front view of the coating and developing treatment system inFIG. 1;

FIG. 4 is a rear view of the coating and developing treatment system inFIG. 1;

FIG. 5 is an explanatory view of a vertical cross section schematicallyshowing the configuration of a resist coating unit;

FIG. 6 is an explanatory view of a horizontal cross sectionschematically showing the configuration of the resist coating unit;

FIG. 7 is an explanatory view showing the configuration of a resistsolution supply mechanism;

FIG. 8 is an explanatory view showing an example of a setting screen;

FIG. 9 is an explanatory view showing an example of giving prioritylevels to pre-dispenses;

FIG. 10 is an explanatory view showing an example of a flow ofperforming the pre-dispense;

FIG. 11 is an explanatory view showing an example of a flow ofperforming the pre-dispense;

FIG. 12 is an explanatory view showing an example of a flow ofperforming the pre-dispense;

FIG. 13 is an explanatory view showing another example of givingpriority levels to the pre-dispenses;

FIG. 14 is an explanatory view of a vertical cross section schematicallyshowing the configuration of another example of the resist coating unit;

FIG. 15 is an explanatory view of a horizontal cross sectionschematically showing the configuration of the other example of theresist coating unit;

FIG. 16 is an explanatory view showing another configuration of a supplymechanism for resist solution supply nozzles;

FIG. 17 is an explanatory view showing a flow of a treatment betweentreatments for lots;

FIG. 18 is a table showing the number of rotations of a wafer in eachstep of a resist coating treatment; and

FIG. 19 is an explanatory view of a vertical cross section showinganother example of the configuration of a cleaning bath.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed. FIG. 1 is a perspective view of a coating and developingtreatment system 1 capable of implementing a substrate treatment methodaccording to the this embodiment, and FIG. 2 is a plane viewschematically showing the configuration of the coating and developingtreatment system 1.

As shown in FIG. 1 and FIG. 2, the coating and developing treatmentsystem 1 has a configuration in which a cassette station 2 for carrying,for example, 25 wafers W in a unit of cassette from/to the outsideto/from the coating and developing treatment system 1 and for carryingthe wafers W to/from a cassette C, a processing station 3 composed ofvarious kinds of processing units which are disposed in multi-tiers, forperforming predetermined processing for the wafers W one by one incoating and developing processes, and an interface section 4 fordelivering/receiving the wafers W to/from an aligner (not-shown) whichis provided adjacent to the processing station 3 are integrallyconnected.

In the cassette station 2, as shown in FIG. 2, a plurality of thecassettes C are mountable, as shown in FIG. 2, in predeterminedpositions on a cassette mounting table 5, which serves as a mountingportion, in a line in an X-direction (a vertical direction in FIG. 2).Furthermore, a wafer carrier 7, which is transportable in the alignmentdirection of the cassettes (the X-direction) and in an alignmentdirection of the wafers W housed in the cassette C (a Z-direction; avertical direction), is provided to be movable along a carrier path 8 sothat it can selectively access to each of the cassettes C.

The wafer carrier 7 has an alignment function for aligning the wafers W.The wafer carrier 7 can access to an extension unit 32 included in athird processing unit group G3 on the processing station 3 side as willbe described below. In the cassette station 2, as shown in FIG. 1, acontrol section 9 is provided which conducts setting and control for thevarious kinds of processing units.

In the processing station 3, a main carrier 13 is provided in a centerpart thereof, and various kinds of the processing units are multi-tieredon a periphery of the main carrier 13 to constitute processing unitgroups. In the coating and developing treatment system 1, where fourprocessing unit groups G1, G2, G3 and G4 are arranged, the first andsecond processing unit groups G1 and G2 are disposed on a front side ofthe coating and developing treatment system 1, the third processing unitgroup G3 is disposed adjacent to the cassette station 2, and the fourthprocessing unit group G4 is disposed adjacent to the interface section4. Furthermore, a fifth processing unit group G5 depicted by a brokenline is allowed to be additionally disposed on a rear side as an option.The main carrier 13 is capable of carrying the wafers W to/from thevarious kinds of later described processing units which are disposed inthese processing unit groups G1, G2, G3, G4 and G5. Incidentally, thenumber and the arrangement of the processing unit groups are differentdepending on the kind of processing performed on the wafers W, and thenumber of the processing unit groups is arbitrarily selected.

In the first processing unit group G1, for example, as shown in FIG. 3,a resist coating unit 17, in which the substrate treatment methodaccording to this embodiment is implemented and a developing unit 18 fordeveloping the wafer W after exposure are two-tiered in the order fromthe bottom. Similarly, in the processing unit group G2, a resist coatingunit 19 and a developing unit 20 are two-tiered in the order from thebottom.

In the third processing unit group G3, for example, as shown in FIG. 4,a cooling unit 30 for cooling the wafer W, an adhesion unit 31 forenhancing adhesion between a resist solution and the wafer W, theextension unit 32 for delivering/receiving the wafers W, pre-bakingunits 33 and 34 for drying a solvent in the resist solution, and apost-baking unit 35 for performing a heat treatment after a developingtreatment are, for example, six-tiered in the order from the bottom.

In the fourth processing unit group G4, for example, a cooling unit 40,an extension and cooling unit 41 for allowing the wafer W mountedthereon to naturally cool, an extension unit 42, a cooling unit 43,post-exposure baking units 44 and 45 for performing a heat treatmentafter exposure, and a post-baking unit 46 are, for example, seven-tieredin the order from the bottom.

In a center part of the interface section 4, as shown in FIG. 2, forexample, a wafer carrier 56 is provided. The wafer carrier 56 isconfigured to be freely movable in the X-direction (the verticaldirection in FIG. 2 and the Z-direction (the perpendicular direction),and, to be freely rotatable in a θ-direction (a direction of rotationabout the Z-axis). Therefore, the wafer carrier 56 can access to theextension and cooling unit 41 and the extension unit 42 which areincluded in the fourth processing unit group G4, an edge exposure unit51, and the not-shown aligner to carry the wafer W to each of them.

Next, the configuration of the aforementioned resist coating unit 17will be described. FIG. 5 is an explanatory view of a vertical crosssection schematically showing the configuration of the resist coatingunit 17, and FIG. 6 is an explanatory view of a horizontal cross sectionof the resist coating unit 17.

The resist coating unit 17 has, for example, as shown in FIG. 5, acasing 17 a, and at a center part thereof a spin chuck 50 is providedfor holding and rotating the wafer W. This spin chuck 50, which isdriven by a driver 57 provided with a motor, a cylinder, and the like,can rotate, for example, at a predetermined speed and rise and lower.

The outside of the spin chuck 50 is surrounded by an almost cylindricalcup 52 with an open upper face. This cup 52 can receive and collect theresist solution and the like splashing from the wafer W. A bottom face52 a of the cup 52 is provided with a drain pipe 53 for draining thecollected resist solution and the like, and an exhaust pipe 54 forexhausting an atmosphere in the cup 52.

Inside the cup 52 and below the wafer W held on the spin chuck 50,cleaning solution supply nozzles 55 are provided. The cleaning solutionsupply nozzles 55 can supply a cleaning solution such as a thinner orthe like to the rear face of the wafer W to clean the rear face of thewafer W.

The resist coating unit 17 is provided with a nozzle 60 for supplyingthe resist solution to the wafer W. The nozzle 60 is supported by anozzle arm 62. The nozzle arm 62 can move, for example, on a rail 63extending in the Y-direction provided on the negative side in theX-direction (on the left side in FIG. 6) with respect to the cup 52, forexample, as shown in FIG. 6. The nozzle arm 62 is moved, for example, bya not-shown driver. On the negative side in the Y-direction with respectto the cup 52, for example, a waiting section S of the nozzle 60 isprovided, and the nozzle arm 62 can move to a position above the waitingsection S. Therefore, the nozzle arm 62 can move the nozzle 60 at thewaiting section S to a position above the center portion of the wafer Win the cup 52.

The following description will be made on one example of a resistsolution supply mechanism K for supplying the resist solution to thenozzle 60 with reference to FIG. 7.

The nozzle 60 is communicated and connected with a, storage tank 71, forexample, via a first pipe 70. The storage tank 71 is communicated andconnected with a solution bottle 73, which is a supply source of theresist solution, via a second pipe 72. The second pipe 72 is providedwith a pump 74 which can replenish the storage tank 71 with the resistsolution in the solution bottle 73. The first pipe 70 is provided with adischarge pump 75, a first valve 76, a filter 77, and a second valve 78in this order, for example, from the storage tank 71 side.

The discharge pump 75 sucks a predetermined amount of the resistsolution in the storage tank 71 and feeds it by pressure to the nozzle60, and, for example, a diaphragm type pump is used as the dischargepump 75. The discharge pump 75 is provided with a purge pipe 79communicated with the second pipe 72, for exhausting bubbles collectingin the discharge pump 75. The purge pipe 79 is provided with anopen/close valve 80. Opening the open/close valve 80 with the dischargepump 75 being operated allows bubbles collecting in the discharge pump75 to be exhausted with the resist solution into the storage tank 71. Inother words, a pre-dispense D1 can be performed for the purpose ofexhausting the bubble in the discharge pump 75.

The filter 77 is for removing impurities contained in the resistsolution. This filter 77 is connected with a vent pipe 81 which exhauststhe bubbles collecting, for example, in the filter 77 to the outside ofthe resist coating unit 17. The vent pipe 81 is provided with anopen/close valve 82. Opening the open/close valve 82 with the dischargepump 75 being operated allows bubbles in the filter 77 to be exhausted.In other words, a pre-dispense D2 can be performed for the purpose ofexhausting the bubble in the filter 77.

The second valve 78 opens and closes to start and stop the discharge ofthe resist solution by the discharge pump 60. Opening the second valve78 and operating the discharge pump 75 allow the resist solution in thestorage tank 71 to be discharged from the nozzle 60. In other words, thesecond valve 78 can perform a pre-dispense D3 for the purpose ofpreventing the nozzle 60 from drying and a pre-dispense D4 for thepurpose of stabilizing the discharge solution as well as the supply ofthe resist solution to the wafer W.

Actions of parts of the discharge pump 75 and so on in the resistsolution supply mechanism K, are controlled by a main controller 85provided, for example, in the control section 9. Therefore, thepre-dispenses of the resist solution performed in the resist solutionsupply mechanism K can be controlled by the main controller 85. In themain controller 85, a recipe, for example, the discharge amount andstart condition of dispense can be set for each of the above-describedpre-dispenses D1 to D4 having the different purposes.

In the main controller 85, a set time is provided for each of thepre-dispenses D1 to D4. The main controller 85 has a not-shown measuringunit 85 a. When the integrated time measured by this measuring unit 85 aexceeds the aforementioned set time, each of the pre-dispenses D1 to D4is performed.

In other words, the start condition in this embodiment is time conditionthat the integrated time of each of the pre-dispenses D1 to D4 exceedseach of the set times. The integrated time is counted from the precedingperformance of the same kind of pre-dispense or from the preceding resetof the integrated time. As for the set times of the pre-dispenses D1 toD4, for example, the pre-dispense D1 is set to 1000 sec, thepre-dispense D2 to 500 sec, the pre-dispense D3 to 500 sec, and thepre-dispense D4 to 1000 sec.

On the other hand, each of the discharge amounts of the pre-dispenses D1to D4 is set to, for example, a minimal amount for attaining the purposeof each of the pre-dispenses D1 to D4. For example, the pre-dispense D1is set to 100 cc, the pre-dispense D2 to 100 cc, the pre-dispense D3 to10 cc, and the pre-dispense D4 to 10 cc. These time conditions anddischarge amounts can be set, for example, on a setting screen T that isan input means of the control section 9 shown in FIG. 1. On the settingscreen T, the time conditions and the discharge amounts of thepre-dispenses D1 to D4 can be set by a touch panel system, for example,as shown in FIG. 8.

In the main controller 85, priority levels can be set for thepre-dispenses D1 to D4. When a pre-dispense at a high priority level isperformed, the counts of the integrated times of pre-dispenses atpriority levels lower than that are reset. On the other hand, when apre-dispense at a low priority level is performed, the counts of theintegrated times for pre-dispenses at priority levels higher than thatare continued.

It is also possible to set in the main controller 85 the pre-dispensesD1 to D4 as pre-dispenses with no priority level, that is, pre-dispensesat independent priority levels (independent of the other pre-dispenseswith given priority levels). In other words, the pre-dispenses at theindependent priority levels are performed based on independent startconditions irrespective of performance or non-performance ofpre-dispenses with given priority levels.

In this embodiment, for example, the pre-dispense D1 is set to apriority level {circle around (1)}, and the pre-dispense D2 is set to apriority level {circle around (2)} lower than the priority level {circlearound (1)} as shown in FIG. 9. The pre-dispenses D3 and D4 are set toindependent priority levels A. It should be noted that in thisembodiment, when the pre-dispense D1 is performed, the pre-dispense D2in that cycle is not performed. Therefore, the discharge amount of thepre-dispense D1 is matched to the discharge amount of the pre-dispenseD2 to attain sufficiently the purpose of the pre-dispense D2.

To an upper face of the casing 17 a, a duct 86 is connected whichsupplies the inside of the cup 52 with nitrogen gas, inert gas, air, orthe like which is controlled in temperature and humidity and cleaned asshown in FIG. 5. This allows the gas to be supplied to maintain apredetermined atmosphere in the cup 52, for example, during the coatingtreatment of the wafer W and during the pre-dispense of the resistsolution.

Next, the method for treating the wafer W performed in the resistcoating unit 17 configured as above will be described together with aseries of photolithography processes performed in the coating anddeveloping treatment system 1.

First, one unprocessed wafer W is taken out of the cassette C by thewafer carrier 7 and carried to the extension unit 32 included in thethird processing unit group G3. Then, the wafer W is carried by the maincarrier 13 into the adhesion unit 31 where the wafer W is coated with,for example, HMDS for enhancing adhesion to the resist solution.Subsequently, the wafer W is carried to the cooling unit 30 and cooledto a predetermined temperature. The wafer W cooled to the predeterminedtemperature is carried by the main carrier 13, for example, to theresist coating unit 17.

The wafer W for which a resist coating treatment as substrate treatmenthas been finished in the resist coating unit 17 is carried by the maincarrier 13 to the pre-baking unit 33, the extension and cooling unit 41in sequence, and further carried by the wafer carrier 56 to the edgeexposure unit 51 and the aligner (not-shown) in sequence so that thewafer W is subjected to predetermined processing in each unit. Then, thewafer W for which exposure has been finished is returned to theextension unit 42 by the wafer carrier 56, and thereafter carried by theman carrier 13 to the post-exposure baking unit 44, the cooling unit 43,the developing unit 18, the post-baking unit 46, and the cooling unit 30in sequence so that the wafer W is subjected to predetermined processingin each unit. Thereafter, the wafer W is returned to the cassette C viathe extension unit 32, and a series of photolithography processes comesto an end.

In the aforementioned resist coating treatment, when the wafer W isfirst carried by the main carrier 13 into the casing 17 a andsuction-held by the spin chuck 50, the spin chuck 50 lowers so that thewafer W is housed in the cup 52. Subsequently, the nozzle 60 waiting atthe waiting section S is moved by the nozzle arm 62 to the positionabove the center portion of the wafer W.

Thereafter, the main controller 85 issues an instruction to operate thedischarge pump 75 and to open the first valve 76 and the second valve78. This causes a predetermined amount of the resist solution to bedischarged onto the center part of the wafer W. Subsequently, the waferW is rotated at a predetermined rotation speed, so that the resistsolution on the wafer W is spread over the entire front face of thewafer W. Thereafter, the rotation speed of the wafer W is increased toadjust the film thickness of the solution film of the resist solution onthe wafer W.

After the adjustment of the film thickness, the rotation speed of thewafer W is decreased, and the rear face of the wafer W is cleaned by thecleaning solution supply nozzles 55. Thereafter, the wafer W is keptrotated to be dried by spinning off the cleaning solution.

After the completion of the dry processing of the wafer W, the rotationof the wafer W is stopped, and the wafer W is delivered from the spinchuck 50 to the main carrier 13 to be carried out of the casing 17 a. Inthe resist coating unit 17, the resist coating treatment is repeated forthe wafers which are loaded in the unit in succession.

For example, during the repeated above-described resist coatingtreatments, when any one of the time conditions of the pre-dispenses D1to D4 is established, the pre-dispense in the resist solution supplymechanism K is performed. When the time condition of the pre-dispense D1at the priority level {circle around (1)} is established, for example,as shown in FIG. 10, the pre-dispense D1 is performed. In thispre-dispense D1, for example, the open/close valves 80 and 82 and thefirst valve 76 are opened, and the discharge pump 75 is operated. Thispermits the discharge pump 75 to feed the set discharge amount of theresist solution by pressure to the vent pipe 81 as to exhaust via thevent pipe 81 the bubbles in the filter 77 together with the resistsolution. In this event, opening the open/close valve 80 permits alsothe bubbles in the discharge pump 75 to be exhausted via the purge pipe79. In short, the purpose of the pre-dispense D2 is also attained.

After the completion of the pre-dispense D1, the count of the integratedtime of the pre-dispense D1 is reset. In this event, the count of theintegrated time of the pre-dispense D2 at the priority level lower thanthe first pre-dispense D1 is also reset. Note that the counts of theintegrated times of the pre-dispenses D3 and D4 are continued.

When the condition of the pre-dispense D2 at the priority level {circlearound (2)} is established, the pre-dispense D2 is performed as shown inFIG. 11. This pre-dispense D2 is performed by operating the dischargepump 75 with the open/close valve 80 opened. This pre-dispense D2 isperformed with the first valve 76 closed and with no pressure impressedon the filter 77 side, so that only the purpose of the pre-dispense D2is attained. After the completion of the pre-dispense D2, the count ofthe integrated time of the pre-dispense D2 is reset, and the counts ofthe integrated times of the other pre-dispenses D1, D3, and D4 arecontinued.

Further, the time condition of the pre-dispense D3 at the independentpriority level A is established as shown in FIG. 12, the pre-dispense D3is performed. For example, the pre-dispense D3 is performed with thedischarge pump 75 operated, the first valve 76 and the second valve 78opened, and the open/close valves 80 and 82 closed. After the completionof the pre-dispense D3, the count of only the integrated time of theperformed pre-dispense D3 is reset. The counts of the integrated timesof the other pre-dispenses at the priority level {circle around (1)} andthe priority level {circle around (2)} and the pre-dispense D4 at theindependent priority level A are continued. Note that when the timecondition of the pre-dispense D4 at the independent priority level A isestablished, the same action as that in the pre-dispense D3 isperformed.

According to the above embodiment, since the recipe and time conditioncan be set for each of the dispenses D1 to D4 for different purposes, anecessary and sufficient pre-dispense can be performed to fill eachpurpose. This results in prevention of an unintentional discharge amountand discharge of the resist solution at an unnecessary timing, therebyreducing the consumption of the resist solution. Further, theperformance of the pre-dispense never stops the coating process for thewafer W, resulting in improved throughput of the wafer processing.

In this embodiment, the pre-dispenses D1 to D4 are given priority levelsso that when a pre-dispense at a high priority level is performed, thecount of the integrated time of a pre-dispenses at a lower prioritylevel is reset. This permits, for example, the pre-dispense D1, whichcan also attain the purpose of the pre-dispense D2, to be set to a highpriority level, thereby reducing the number of unnecessary pre-dispensesD2. Therefore, it is possible to omit unnecessary pre-dispenses andreduce the consumption of the resist solution.

The pre-dispenses D3 and D4 at the independent priority levels A whichare performed independently of priority levels but based only on the owntime conditions, thereby enabling reliable performance of an importantpre-dispense whose purpose cannot be attained by the other pre-dispense.

Note that the kinds and purposes of the pre-dispenses described in theabove embodiment can be arbitrarily changed in accordance with theconfiguration of the resist solution supply mechanism and so on. In thiscase, it is also adoptable to give priority levels to all pre-dispenseswith no pre-dispense placed at the independent priority level, orconversely, to give the independent priority levels to all thepre-dispenses.

While one kind of pre-dispense is set to each priority level in thisabove embodiment, a plurality of pre-dispenses may be set to the samepriority level. In this case, for example, the pre-dispenses D1 and D3are placed at the priority level {circle around (1)} as shown in FIG.13. After the pre-dispense D1 is performed and completed, the count ofthe integrated time of the pre-dispense D3 is not reset but continued.On the other hand, when the pre-dispense D3 is performed, the count ofthe integrated time of the pre-dispense D1 is not reset but continued.This ensures independence of the time conditions at the same prioritylevel {circle around (1)} with the above-described priority maintainedwith respect to the priority level {circle around (2)}.

While the start conditions of the pre-dispenses D1 to D4 described inthe above embodiment are time conditions, other start conditions may beadopted. For example, it is also adopted that the integrated number oftreated wafers from the time of a preceding pre-dispense or the time ofa preceding reset is measured for every pre-dispense, so that each ofthe pre-dispenses D1 to D4 is performed when the integrated number oftreated wafers exceeds a set number of treated wafers. In this case, forexample, the measuring unit 85 a of the main controller 85 is providedwith a function of measuring the number of treated wafers. Set numbersof treated wafers for the pre-dispenses D1 to D4 are set in the maincontroller 85. Further, the pre-dispenses D1 to D4 are given theabove-described priority levels so that when a pre-dispense at a highpriority level is performed, the integrated number of treated wafers ofthe pre-dispense at a lower priority level is reset. Besides, when apre-dispense at a low priority level is performed, the integrated numberof treated wafers of the pre-dispense at a higher priority level iscontinued. Also in this case, it is possible to omit unnecessarypre-dispenses and reduce the number of pre-dispenses.

Further, the start condition of the pre-dispense may be satisfaction ofeither condition that the above-described integrated time has elapsedthe set time or that the above-described integrated number of treatedwafers exceeds the set number of treated wafers. In this case, similarlyto the above-described embodiment, when a pre-dispense at a highpriority level is performed, the integrated time and the integratednumber of treated wafers of a pre-dispense at a lower priority level arereset. Besides, when a pre-dispense at a low priority level isperformed, the integrated time and the integrated number of treatedwafers of a pre-dispense at a higher priority level are continued.

Next, another embodiment will be described. FIG. 14 is an explanatoryview of a vertical cross section schematically showing the configurationof the resist coating unit 17 having another configuration, and FIG. 15is an explanatory view of a horizontal cross section of the resistcoating unit 17.

In this resist coating unit 17, two resist solution supply nozzles 160and 161 are provided which supply the resist solution to the wafer W,for example, as shown in FIG. 15. The resist solution supply nozzles 160and 161 are held by a nozzle arm 162 as shown in FIG. 14. The nozzle arm162 is composed of a support post 163 extending, for example, in thevertical direction, a horizontal shaft 164 extending from the supportpost 163 in the horizontal direction, for example, in the X-direction,and a holding section 165 for holding the resist solution supply nozzles160 and 161.

The support post 163 is capable of expansion and contraction in thevertical direction, for example, by a driving mechanism such as acylinder or the like, and the horizontal shaft 164 is also capable ofexpansion and contraction in the horizontal direction, for example, by adriving mechanism such as a motor or the like. This allows the holdingsection 165 to be moved in the vertical direction and the X-direction.The holding section 165 is provided, for example with a removalmechanism (not shown) such a solenoid or the like, so that the holdingsection 165 can hold and remove the resist solution supply nozzle 160 or161 at a predetermined timing.

As shown in FIG. 15, a rail 166 extending in the Y-direction is providedon the negative side in the X-direction (on the left side in FIG. 15)with respect to the cup 52 so that the nozzle arm 162 is provided tofreely move on the rail 166 by a driving mechanism (not-shown). Thispermits the nozzle arm 162 to move from a later-described waitingsection S of the resist solution supply nozzles 160 and 161 to theposition above the cup 52, so that the nozzle arm 162 can carry theresist solution supply nozzles 160 and 161 within a section between theaforementioned positions.

In the waiting section S, for example, two resist solution supplynozzles 160 and 161 can wait. In the waiting section S, for example, acleaning bath 167 is provided which stores a cleaning solution such as athinner or the like. The cleaning bath 167 is provided with a cleaningsolution supply pipe 168 for supplying the cleaning solution into thecleaning bath 167 and a drain pipe 169 for draining the cleaningsolution and the like in the cleaning bath 167. A predetermined amountof the cleaning solution is stored in the cleaning bath 167 so that theresist solution supply nozzles 160 and 161 during waiting can beimmersed in the cleaning solution. Further, it is also possible toperform pre-dispenses of the resist solution from the resist solutionsupply nozzles 160 and 161 into the cleaning bath 167 and drain thedischarged resist solution via the drain pipe 169.

The resist solution supply nozzles 160 and 161 are respectivelyconnected to supply pipes 170 and 171 which are respectivelycommunicated and connected with storage tanks 172 an 173 which aresupply sources of the resist solution, for example, as shown in FIG. 16.The storage tank 172 stores a resist solution A, and the storage tank173 stores a resist solution B. Therefore, the resist solution supplynozzle 160 discharges the resist solution A supplied from the storagetank 172 via the supply pipe 170, and the resist solution supply nozzle161 discharges the resist solution B supplied from the storage tank 173via the supply pipe 171.

The supply pipes 170 and 171 are respectively provided with pumps 174and 175 for feeding by pressure the resist solutions to the resistsolution supply nozzles 160 and 161, and adjusting valves 176 and 177for controlling the discharge amounts of the resist solutions.

Actions of the pumps 174 and 175 and the adjusting valves 176 and 177are controlled, for example, by a main controller 178. The maincontroller 178 can also control actions of other driving mechanisms ofthe resist coating unit 17, for example, the driver 57 and so on, thuscontrolling the entire resist coating unit 17. It should be noted thatthe main controller 178 is composed of a controlling unit (not shown)such as a CPU or the like, a storage unit (not shown) such as a RAM orthe like, an input unit (not shown) for inputting set values and so on,an output unit (not shown) for outputting instruction signals to driversand so on.

The main controller 178 stores a treatment program P1 with treatmentconditions set for the wafers W in every lot. The main controller 178executes, the treatment program P1 to thereby control the pumps 174 and175, the adjusting valves 176 and 177, and so on for performance of apredetermined treatment for each lot.

The main controller 178 stores a determination program P2, for example,for determining whether to perform a pre-dispense of the resistsolution. Through execution of the determination program P2, the maincontroller 178 determines to perform the pre-dispense when any one ofthe following conditions is satisfied, for example, the kind of theresist solution is changed between treatments for sequential lots(condition {circle around (1)}), a lapse time T from the completion ofthe treatment for the preceding lot exceeds a previously set allowedtime T_(M), for example, 600 sec (condition {circle around (2)}), andthe number of treated lots N after the performance of the precedingpre-dispense exceeds a previously set allowed number of treated lotsN_(M), for example, 10 lots (condition {circle around (3)}). The maincontroller 178 determines to perform no pre-dispense when no conditionis satisfied. When determining to perform a pre-dispense, the maincontroller 178 issues an instruction to operate the pumps 174 and 175and so on for performance a pre-dispense.

The above condition {circle around (1)} that whether the kind of theresist solution is changed can be recognized, for example, from the setcondition of the treatment program P1. Further, the main controller 178includes, for example, a time measuring function 179 and a function ofcounting the number of treated lots 180 so that the lapse time T in thecondition {circle around (2)} can be measured by the time measuringfunction 179, and the number of treated lots N in the condition {circlearound (3)} can be measured by the function of counting the number oftreated lots 180. The function of counting the number of treated lots180 is reset every performance of pre-dispense so that the count numberis returned to zero.

To an upper face of the casing 17 a, a duct 181 is connected whichsupplies the inside of the cup 52 with nitrogen gas, inert gas, air, orthe like which is controlled in temperature and humidity and cleaned asshown in FIG. 14. This allows the gas to be supplied, for example,during the coating treatment of the wafer W and during the pre-dispenseof the resist solution, so as to maintain a predetermined atmosphere inthe cup 52.

Next, the method for treating the wafer W performed in the resistcoating unit 17 configured as above will be described.

At the time of starting up the coating and developing treatment system1, that is, at the time of starting treatment for the first lot, forexample, a pre-dispense is performed for the resist solution A from theresist solution supply nozzle 160 used in the treatment for this lot.Then, the treatment program P1 is executed in the wafer treatment ineach lot, so that the resist coating treatment is performed inaccordance with the treatment program P1.

For example, before the wafer W is carried into the casing 17 a, the aircontrolled at predetermined temperature and humidity is supplied fromthe duct 181 to maintain a predetermined atmosphere inside the casing 17a. In this event, the supplied air is exhausted to the outside of theresist coating unit 17 via the exhaust pipe 54.

When the wafer W is carried by the main carrier 13 into the casing 17 a,the wafer W is delivered to the spin chuck 50, which has been raised,and suction-held on the spin chuck 50. Subsequently, the spin chuck 50is lowered so that the wafer W is housed in the cup 52. Then, forexample, the resist solution supply nozzle 160 waiting in the waitingsection S is held by the nozzle arm 162 and moved to the position abovethe center portion of the wafer W in the cup 52.

When the resist solution supply nozzle 160 is located above the centerportion of the wafer W, the main controller 178 issues an instruction tooperate the pump 174 and the adjusting valve 176 so that the resistsolution supply nozzle 160 discharges a predetermined amount of theresist solution A. Thereby, a predetermined amount of the resistsolution A is supplied onto the center portion of the wafer W.Subsequently, the wafer W is rotated at a predetermined rotation speed,for example, 1500 rpm, and this rotation of the wafer W spreads theresist solution A over the front face of the wafer W. After thespreading of the resist solution is performed for a predetermined periodso that the resist solution is spread over the entire front face of thewafer W, the rotation speed of the wafer W is increased to, for example,2000 rpm to adjust the film thickness of the solution film of the resistsolution on the wafer W.

After the adjustment of the film thickness, the rotation speed of thewafer W is decreased, for example, to 500 rpm. Then, the cleaningsolution supply nozzles 55 supply a cleaning solution such as a thinneror the like to the rear face of the wafer W to clean the rear face ofthe wafer W. Thereafter, the supply of the cleaning solution is stopped,and the wafer W is kept rotated, for example, at 500 rpm so that thewafer is subjected to dry processing.

After the completion of the dry processing of the wafer W, the rotationof the wafer W is stopped, and the wafer W is delivered from the spinchuck 50 to the main carrier 13 and carried out of the casing 17 a, anda series of resist coating treatment of the wafer W comes to an end.

After the completion of the resist coating treatment of the wafer W, asubsequent wafer is immediately carried in, and subjected to the sametreatment. In this manner, a predetermined number of wafers are treatedone by one, and the treatment of this lot comes to an end.

After the completion of the treatment, for example, for a lot L1 asshown in FIG. 17, the time measuring function 179 starts measuring time.Then, immediately before the start of a treatment, for example, for asubsequent lot L2, the main controller 178 executes the determinationprogram P2 to determine whether the above-described conditions {circlearound (1)} to {circle around (3)} are satisfied. More specifically, thefollowing is determined, that is, whether the resist solution to be usedin the subsequent lot L2 is the resist solution B different from theresist solution A for the lot L1, whether the lapse time T>the allowedtime T_(M), or whether the number of treated lots N>the allowed numberof treated lots N_(M). When any one of the conditions {circle around(1)} to {circle around (3)} is satisfied, the pump 175 or 176 andadjusting valve 176 or 177 for the resist solution to be used for thesubsequent lot L2 are operated to perform a pre-dispense of the resistsolution before the subsequent wafer is carried into the resist coatingunit 17.

In this event, the resist solution supply nozzles 160 and 161 arelocated in the cleaning bath 167, so that this pre-dispense is performedin the cleaning bath 167. Then, the time measuring function 179 and thefunction of counting the number of treated lots 180 are reset.

On the other hand, if any one of the above conditions {circle around(1)} to {circle around (3)} is not satisfied, no pre-dispense isperformed, for example, the execution of the determination program P2 isended, and a treatment for the subsequent lot L2 is started. Asdescribed above, the main controller 178 executes the determinationprogram P2 every completion of a treatment for one lot to determinewhether the above-described conditions {circle around (1)} to {circlearound (3)} are satisfied. When any one of the conditions is satisfied,a pre-dispense is performed, and when none of the conditions issatisfied, no pre-dispense is performed.

According to the embodiment, since a pre-dispense is performed only whenany one of the conditions {circle around (1)} to {circle around (3)} issatisfied, the number of pre-dispenses can be reduced as compared to theprior art in which the pre-dispense is performed every change of lot.This results in reduced consumption of the resist solution. Since apre-dispense is performed when the kind of the resist solution ischanged between treatments for lots, a resist solution can be drainedwhich has not been used in treatment for the preceding lot and hasremained and deteriorated in the resist solution supply nozzle 160 or161 and the supply pipe 170 or 171. This can prevent the resist solutionchanged in quality from being supplied onto the wafer W.

Besides, a pre-dispense is performed also when time of the allowed timeT_(M) has elapsed after the completion of the treatment for thepreceding lot. In other words, a pre-dispense is performed also whenthere has been an idle time to the start of the treatment for thesubsequent lot and thus the resist solution has remained anddeteriorated in the resist solution supply nozzle 160 or 161 and thesupply pipe 170 or 171. This can prevent the deteriorated resistsolution from being discharged onto the wafer W. Further, a pre-dispenseis performed also when the number of treated lots N after performance ofthe preceding pre-dispense exceeds the allowed number of treated lotsN_(M), so that the bubbles gradually accumulated, for example, in thepumps 174 and 175 can be eliminated to prevent the bubbles from beingmixed in the resist solution during treatment. Note that it is alsoadoptable that, for example, in the case of treatment for one lot whichnormally has 25 wafers and when a lot having 12 wafers or less isincluded in the treatments for the successive lots, the lot having 1wafers or less is counted as a ½ lot.

In this embodiment, the count of the number of treated lots N is resetevery performance of pre-dispense, and as a result, the conditions{circle around (1)} and {circle around (2)} are not successivelysatisfied but the condition {circle around (3)} is satisfied only whenthe number of treated lots N exceeds the allowed number of treated lotsN_(M). This eliminates performance of a pre-dispense based on thecondition {circle around (3)} immediately after performance of apre-dispense based on the condition {circle around (1)}, resulting inreduced number of pre-dispenses.

Since a pre-dispense is performed at the start of the treatment for thefirst lot, the treatment can be performed using a desired resistsolution from the treatment for the first lot.

The above embodiment describes two systems of resist solution supplypipes, but the number of nozzles is not limited to the above, and anarbitrary number (a plurality) of nozzles can be selected.

While, the condition {circle around (1)} is that the kind of the resistsolution is changed between lots in the above embodiment, the condition{circle around (1)} may be that the number of rotations of the wafer Wduring a predetermined step in the resist coating treatment is changedbetween lots.

For example, as shown in FIG. 18, it is assumed that the resist coatingtreatment includes three steps, for example, Step S1 in which the waferW is rotated, for example, at a first rotation number R1, for example,2000 rpm so that the temperature of the front face of the wafer is madeeven; Step S2 in which the wafer W is rotated, for example, at a secondrotation number R2, for example, 3500 rpm, and the resist solution isdropped onto the wafer W to form a resist film on the wafer W; and StepS3 in which the wafer W is rotated, for example, at a third rotationnumber R3, for example, 2500 rpm so that the resist film on the wafer Wis stabilized and further the resist film is dried. Then, for example,the fact that the second rotation number R2 in Step S2 in the resistcoating treatment is changed between lots may be regarded as thecondition {circle around (1)}. This Step S2 is accompanied by spreadingof the resist solution on the front face of the wafer W, and thus therotation number R2 is determined by the viscosity of the resist solutionand so on. The different kind of resist solution leads to a differentviscosity of the resist solution and a different rotation number R2.Therefore, the object of determination for the condition {circle around(1)} is set not to the kind of the resist solution but to the rotationnumber R2 in Step S2 in the resist coating treatment, in whichsubstantially the same effect can be attained. Note that in place ofStep S2, the rotation number R1 or R3 in the other Step S1 or S3 may bemade the object of determination for the condition {circle around (1)}.

The allowed time T_(M) in the condition {circle around (2)} may beappropriately determined based on the viscosity of the resist solutionin use, the kind of a solvent contained in the resist solution, aphotosensitizer component, or the like. For example, deteriorationtimes, drying times, or the like of a plurality of resist solutions areobtained by experiments to calculate appropriate allowed times inadvance for the respective resist solutions. The appropriate allowedtimes are stored, for example, in the main controller 178 so that whenthe treatment program P1, is programmed, the shortest appropriateallowed time among a plurality of resist solutions for use in thetreatment program is set in the determination program P2 as the allowedtime T_(M). The determination of the allowed time T_(M) in accordancewith the kind of the resist solution as described above permits apre-dispense at an appropriate timing using any of the resist solutions,so as to prevent a deteriorated resist solution from being dischargedonto the wafer W.

The allowed number of treated lots N_(M) in the condition {circle around(3)} may also be determined in accordance with the kind of the resistsolution such as the viscosity of the resist solution in use, the kindof a solvent contained in the resist solution, or the like. Also in thiscase, correlations between various kinds of resist solutions andcontamination at the tip portion of the resist solution supply nozzleare obtained by experiments or the like to calculate appropriate allowednumbers of treated lots in advance for the respective resist solutionsbased on the correlations. The appropriate allowed numbers of treatedlots are stored, for example, in the main controller 178 so that whenthe treatment program P1 is programmed, the smallest appropriate allowednumber of treated lots among a plurality of kinds of resist solutionsfor use in the treatment is set in the determination program P2 as theallowed number of treated lots N_(M). This determines an appropriateallowed number of treated lots N_(M) every time depending on the kind ofthe resist solution for use, resulting in performance of a pre-dispenseat an appropriate timing.

While the condition {circle around (3)} is that the number of treatedlots N after performance of the preceding pre-dispense exceeds theallowed number of treated lots N_(M) in the above embodiment, the numberof treated wafers W may be used in place of the number of treated lots.In this case, the condition {circle around (3)} is that, for example,the number of treated wafers after performance of the precedingpre-dispense exceeds the allowed number of treated wafers. In this case,the number of treated wafers is counted by a function of counting thenumber of treated wafers, so that when any one of the conditions {circlearound (1)} to {circle around (3)} is satisfied, a pre-dispense isperformed. Then, the count of the number of treated wafers is resetevery performance of pre-dispense.

While the conditions {circle around (1)} to {circle around (3)} areselectively imposed as a condition for performance of a pre-dispense inthe above-described embodiment, a pre-dispense may be performed wheneither the condition {circle around (1)} or the condition {circle around(2)} is satisfied, that is, the condition that the kind of the resistsolution is changed between the treatments for sequential lots or thecondition that the allowed time T_(M) has elapsed after the completionof the preceding lot. Also in this case, since no pre-dispense isperformed unless the kind of the resist solution is changed or theallowed time T_(M) has elapsed, the number of pre-dispenses can bereduced. On the other hand, a pre-dispense is performed when necessaryto prevent a deteriorated resist solution from being supplied to thewafer W, so that the resist coating treatment can be appropriatelyperformed.

Further, it is also adoptable to perform a pre-dispense when either thecondition {circle around (1)} or the condition {circle around (3)} issatisfied, that is, the condition that the kind of the resist solutionis changed or the condition that the number of treated lots N afterperformance of the preceding pre-dispense exceeds the allowed number oftreated lots N_(M). Also in this case, since no pre-dispense isperformed unless the kind of the resist solution is changed or thenumber of treated lots N>the allowed number of treated lots N_(M), theconsumption of the resist solution can be reduced accordingly.

It should be noted that a pre-dispense may be performed only in the caseof the condition {circle around (1)}, that is, when the kind of theresist solution is changed between the treatments for sequential lots.Also in this case, the number of pre-dispenses can be reduced ascompared to the prior art, resulting in reduced consumption of theresist solution.

As shown in FIG. 19, a cleaning bath 90 in the resist coating unit 17may comprise, for example, a sealable case 190 a and cleaning solutionjet nozzles 191 and 192 for jetting a cleaning solution to the resistsolution supply nozzles 160 and 161. The upper face of the case 190 a isprovided with insertion ports 193 and 194 for inserting the resistsolution supply nozzles 160 and 161 into the case 190 a. The lower faceof the case 190 a is provided with a cleaning solution supply pipe 195for supplying the cleaning solution into the case 190 a and a drain pipe196 for draining the cleaning solution in the case 190 a.

As for prevention of drying during waiting, a predetermined amount, forexample, 5 cc to 20 cc of the cleaning solution is stored in the lowerpart of the cleaning bath 190 to form a volatile atmosphere of thecleaning solution in the upper portion of the cleaning bath 190 so thatthe resist solution supply nozzles 160 and 161 are housed in thevolatile atmosphere. This allows the tip portions of the resist solutionsupply nozzles 160 and 161 during waiting to be exposed to the volatileatmosphere of the cleaning solution, thereby preventing the resistsolution adhered to the tip portions of the resist solution supplynozzles 160 and 161 from drying.

Further, it is also adoptable to jet the cleaning solution from thecleaning solution jet nozzles 191 and 192 to the waiting resist solutionsupply nozzles 160 and 161, for example, immediately before performanceof a pre-dispense so as to clean and dissolve the resist solutionadhered to the tip portions of the resist solution supply nozzles 160and 161. Thereafter, a pre-dispense is performed, and then the cleaningsolution in the cleaning bath 190 may be drained via the drain pipe 196,and a new cleaning solution is supplied from the cleaning solutionsupply pipe 195 to replace the cleaning solution in the cleaning bath190. This permits the cleaning solution contaminated due topre-dispenses and so on to be replaced with a new cleaning solution.

While the present invention is applied to the treatment method ofperforming a pre-dispense of the resist solution in the above-describedembodiment, the present invention is also applicable to a treatmentmethod of performing pre-dispenses of other treatment solutions, forexample, a developing solution, a cleaning solution, a coating solutionfor forming an interlayer insulating film, a treatment solution for usein the adhesion treatment, and so on. Further, the present invention isalso applicable to a treatment method for substrates other than thewafer W, for example, an LCD substrate, a mask substrate, a reticlesubstrate, and so on.

The present invention is a substrate treatment method in which atreatment by supplying a treatment solution to a substrate issuccessively performed for a plurality of substrates, comprising thestep of, during the performance of the successive treatments, performingbetween the treatments a plurality of pre-dispenses for differentpurposes of the treatment solution, wherein at least a recipe of thetreatment solution to be pre-dispensed or a start condition of thepre-dispense is determined for each of the pre-dispenses.

Note that the “pre-dispense” in the present invention is a pre-dispenseof the treatment solution. This pre-dispense includes not only drainingthe treatment solution remaining in the treatment solution supplymechanism to the outside thereof but also draining the treatmentsolution in the treatment solution supply mechanism to other parts inthe same treatment solution supply mechanism. The “pre-dispense” issometimes called also a “dummy dispense”. Beside, the recipe includes,for example, setting of the discharge rate of the treatment solution.

Further, the present invention can also employ the followingconfiguration. The configuration is such that an integrated time fromthe time of a preceding pre-dispense or the time of a preceding reset ismeasured for each of the pre-dispenses, that each of the pre-dispensesis performed when the integrated time reaches a predetermined set time,that the plurality of pre-dispenses are given priority levels, that whenthe pre-dispense at a high priority level is performed, the integratedtime of the pre-dispense at a priority level lower than that is reset,and that when the pre-dispense at a low priority level is performed, theintegrated time of the pre-dispense at a priority level higher than thatis not reset.

The “time of a preceding reset” here means the time of a preceding resetof the integrated time which is continuously measured. Besides, the“predetermined set time” means a set time determined for eachpre-dispense.

In the pre-dispense performed in the treatment for the substrate,performance of one pre-dispense may sometimes attain the purpose ofanother pre-dispense. For example, when a pump is operated to perform apre-dispense of exhausting bubbles collecting in a filter, apre-dispense of exhausting bubble gathering in the pump can also beperformed at the same time. In this case, for example, the pre-dispenseof exhausting the bubble in the filter is given a high priority level,and the pre-dispense of exhausting the bubble in the pump is given a lowpriority level.

When the, pre-dispense at the high priority level is performed, theintegrated time of the pre-dispense at the lower priority level isreset. Therefore, the performance of the pre-dispense of exhausting thebubbles in the filter omits the immediately subsequent pre-dispense ofexhausting the bubbles in the pump, resulting in reduced total number ofpre-dispenses. This can shorten the suspension time due to thepre-dispenses in the substrate treatment, and reduce the consumption ofthe treatment solution.

Note that as the criteria for giving priority levels, for example, thefollowing can be suggested. As for pre-dispenses performed from the samedraining unit, one needs to be performed frequently is given a highpriority level, and one only needs to be performed infrequently is givena low priority level. In this case, the discharge amount of thetreatment solution may be matched to the largest amount among thepre-dispenses which are given priority levels. Further, the prioritylevels may be given such that among pre-dispenses performed from thesame draining unit, a pre-dispense with a larger discharge amount isgiven a high priority level, and a pre-dispense with a smaller dischargeamount is given a low priority level. Moreover, the priority levels maybe given such that a pre-dispense capable of attaining a plurality ofpurposes is given a high priority level, and a pre-dispense, whosepurpose is attained by performance of the pre-dispense capable ofattaining a plurality of purposes, is given a low priority level.

The same process may be executed using an integrated number of treatedsubstrates in place of the integrated time. Also in this case, it ispossible to omit unnecessary pre-dispenses to reduce the total number ofpre-dispenses. Note that the “predetermined set number of treatedsubstrates” means the set number of treated substrates determined foreach pre-dispense.

Further, it is also adoptable that both the integrated time and theintegrated number of treated substrates are employed, that each of thepre-dispenses is performed when the integrated time reaches apredetermined set time or when the integrated number of treatedsubstrates reaches each set number of treated substrates, that when thepre-dispense at a high priority level is performed, the integrated timeand the integrated number of treated substrates of the pre-dispense at apriority level lower than that are reset, and that when the pre-dispenseat a low priority level is performed, the integrated time and theintegrated number of treated substrates of the pre-dispense at apriority level higher than that are not reset.

Further, within the present invention, it is also adoptable that only apart of the plurality of pre-dispenses as described above are givenpriority levels, that the reset is not performed for the pre-dispensewithout a given priority level when all the other pre-dispenses areperformed, and that the pre-dispense without a given priority level isperformed only in accordance with its own start condition. This allows apre-dispense whose start condition is independent of the otherpre-dispenses to be set and performed.

Further, within the present invention, it is also adoptable that aplurality of pre-dispenses are placed at the same priority level, andthat the reset is not performed for the pre-dispense placed at the samepriority level when the other pre-dispense at the same priority level isperformed. In this case, a plurality of pre-dispenses having independentstart conditions can be set to the same priority level. This enables apre-dispense to be set and performed while keeping its independence ofthe start condition from a certain pre-dispense and allowing startconditions of other pre-dispenses to depend thereon.

The present invention in another aspect is a substrate treatment methodin which a treatment by supplying a treatment solution to a substrate issuccessively performed for a plurality of substrates, comprising thestep of performing a pre-dispense of the treatment solution at a breakbetween lots of the substrates, wherein the step of performing thepre-dispense is performed only when the kind of the supplied treatmentsolution is changed between the lots.

In this case, the pre-dispense step performed at a break between thelots of the substrates may be performed only when either condition issatisfied, a condition that the kind of the supplied treatment solutionis changed between the lots or a condition that a predetermined time haselapsed after completion of the treatment for a preceding lot. The“treatment for a preceding lot” means the treatment for “a lotimmediately before the break of lot.”

If there is a long time from the completion of the treatment for thepreceding lot to the start of the treatment for a new lot, the treatmentsolution in the treatment solution supply mechanism such as nozzles,supply pipes, and so on is susceptible to deterioration. Thus,performance of a pre-dispense also when a predetermined time has elapsedafter the completion of the treatment for the preceding lot sufficientlyensures the quality of the treatment solution to be supplied tosubstrates.

The pre-dispense step performed at a break between the lots of thesubstrates may be performed only when either condition is satisfied, acondition that the kind of the supplied treatment solution is changedbetween the lots or a condition that the treatments for a predeterminednumber of lots are completed after performance of a precedingpre-dispense.

Performance of a pre-dispense also when the treatments for apredetermined number of lots are completed after performance of apreceding pre-dispense makes it possible to eliminate bubbles in thenozzle and supply pipe gradually accumulated, for example, bycontinuously supplying the treatment solution. This can prevent thebubbles from being contained in the treatment solution to be supplied tosubstrates.

The pre-dispense step performed at a break between the lots of thesubstrates may be performed only when any one of conditions issatisfied, a condition that the kind of the treatment solution ischanged between the lots, a condition that a predetermined time haselapsed after completion of the treatment for a preceding lot, and acondition that the treatments for a predetermined number of lots or apredetermined number of substrates are completed after performance of apreceding pre-dispense.

Performance of a pre-dispense also when a predetermined time has elapsedafter the completion of the treatment for a preceding lot makes itpossible to prevent deterioration of the treatment solution to besupplied to substrates. Performance of a pre-dispense when thetreatments for a predetermined number of lots or a predetermined numberof substrates are completed after performance of a precedingpre-dispense makes it possible to drain bubbles in the nozzle and supplypipe accumulated, for example, by continuously supplying the treatmentsolution. This can prevent unnecessary substances such as bubbles and soon from being contained in the treatment solution to be supplied tosubstrates. Note that it is preferable that the preceding pre-dispenseis the last performed one among pre-dispenses previously performed.

It is also possible to propose a method that the number of treated lotsis counted to recognize the predetermined number in the condition, andthat the count of the number of treated lots is reset every performanceof the pre-dispense. This permits the count of the number of lots to bereset even when a pre-dispense is performed based on another conditionsuch as charge of the kind of resist solution or the like. As a result,the pre-dispense based on the condition of the number of treated lots isregarded as has been performed, resulting in reduced frequency ofpre-dispenses.

Further, it is also possible to propose a method that is a substratetreatment method in which a treatment by supplying a treatment solutionto a substrate is successively performed for a plurality of substrates,comprising the step of performing a pre-dispense of the treatmentsolution at a break between the lots of the substrates, wherein the stepof performing the pre-dispense is performed only when any one ofconditions is satisfied, a condition that the kind of the suppliedtreatment solution is changed between the lots, a condition that apredetermined time has elapsed after completion of the treatment for apreceding lot, and a condition that a predetermined number of substrateshave been treated after performance of a preceding pre-dispense.

According to the method, the pre-dispense is performed when the kind ofthe treatment solution is changed between the lots, so that thefrequency of pre-dispenses can be reduced as compared to the prior art.Further, the pre-dispense is performed also when a predetermined timehas elapsed after the completion of the treatment for a preceding lot,thereby making it possible to prevent deterioration of the treatmentsolution to be supplied to substrates. Further, the pre-dispense isperformed also when a predetermined number of substrates have beentreated after performance of a preceding pre-dispense, thereby making itpossible to drain bubbles in the nozzle and supply pipe before a largeamount of bubbles accumulated therein. This can maintain the samequality of the treatment solution to be supplied to substrates. It isalso adoptable that the number of treated substrates is counted torecognize the predetermined number in the condition, and that the countof the number of treated substrates is reset every performance of thepre-dispense.

The pre-dispense may be performed also at the time of starting thetreatment for the first lot. The pre-dispense can be performed beforethe time of starting the treatment for the first lot, for example, atthe time of starting up the treatment unit for implementing thetreatment method. This permits a desired treatment solution to besupplied to substrates from the treatment for the first lot forperformance of an appropriate treatment.

1. A treatment method of performing a substrate treatment to supply atreatment solution to a substrate in sequence for a plurality ofsubstrates, comprising the step of: performing a pre-dispense ofdraining a deteriorated treatment solution at a break between lots ofthe substrates, wherein the step of performing the pre-dispense isperformed only when either condition is satisfied, a condition that thekind of the supplied treatment solution is changed between the lots or acondition that the treatments for a predetermined number of lots havebeen completed after performance of a preceding pre-dispense, andwherein a number of treated lots for which the pre-dispense does notneed to be performed is obtained for each of a plurality of kinds oftreatment solutions in use, and a smallest number of the numbers oftreated lots is set as the predetermined number of treated lots.
 2. Atreatment method of performing a substrate treatment to supply atreatment solution to a substrate in sequence for a plurality ofsubstrates, comprising the step of: performing a pre-dispense ofdraining a deteriorated treatment solution at a break between lots ofthe substrates, wherein the step of performing the pre-dispense isperformed only when any one of conditions is satisfied, a condition thatthe kind of the treatment solution is changed between the lots, acondition that a predetermined time has elapsed after completion of thetreatment for a preceding lot, and a condition that the treatments for apredetermined number of lots have been completed after performance of apreceding pre-dispense, and wherein a number of treated lots for whichthe pre-dispense does not need to be performed is obtained for each of aplurality of kinds of treatment solutions in use, and a smallest numberof the numbers of treated lots is set as the predetermined number oftreated lots.
 3. The method as set forth in claim 1, wherein the numberof treated lots is counted to recognize the predetermined number in thecondition, and wherein the count of the number of treated lots is resetevery performance of the pre-dispense.
 4. The method as set forth inclaim 2, wherein the number of treated lots is counted to recognize thepredetermined number in the condition, and wherein the count of thenumber of treated lots is reset every performance of the pre-dispense.